GB2271560A - Method for reducing the harmful-substance content of flue gases in a furnace unit - Google Patents

Method for reducing the harmful-substance content of flue gases in a furnace unit Download PDF

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Publication number
GB2271560A
GB2271560A GB9320054A GB9320054A GB2271560A GB 2271560 A GB2271560 A GB 2271560A GB 9320054 A GB9320054 A GB 9320054A GB 9320054 A GB9320054 A GB 9320054A GB 2271560 A GB2271560 A GB 2271560A
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GB
United Kingdom
Prior art keywords
furnace
condition
adsorbing medium
carbonate
dust
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB9320054A
Other versions
GB9320054D0 (en
GB2271560B (en
Inventor
Bernd Wendl
Gerald Koeberl
Heinz Kopp
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Veitsch Radex GmbH and Co OG
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Veitsch Radex GmbH and Co OG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication of GB9320054D0 publication Critical patent/GB9320054D0/en
Publication of GB2271560A publication Critical patent/GB2271560A/en
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Publication of GB2271560B publication Critical patent/GB2271560B/en
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/48Sulfur compounds
    • B01D53/50Sulfur oxides
    • B01D53/508Sulfur oxides by treating the gases with solids
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34Chemical or biological purification of waste gases
    • B01D53/46Removing components of defined structure
    • B01D53/68Halogens or halogen compounds
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10LFUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L1/00Liquid carbonaceous fuels
    • C10L1/10Liquid carbonaceous fuels containing additives
    • C10L1/12Inorganic compounds
    • C10L1/1233Inorganic compounds oxygen containing compounds, e.g. oxides, hydroxides, acids and salts thereof
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10LFUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G, C10K; LIQUEFIED PETROLEUM GAS; ADDING MATERIALS TO FUELS OR FIRES TO REDUCE SMOKE OR UNDESIRABLE DEPOSITS OR TO FACILITATE SOOT REMOVAL; FIRELIGHTERS
    • C10L10/00Use of additives to fuels or fires for particular purposes
    • C10L10/02Use of additives to fuels or fires for particular purposes for reducing smoke development

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • General Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Environmental & Geological Engineering (AREA)
  • Analytical Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Biomedical Technology (AREA)
  • Organic Chemistry (AREA)
  • Inorganic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • Treating Waste Gases (AREA)
  • Solid-Sorbent Or Filter-Aiding Compositions (AREA)

Description

2271560 METHOD FOR REDUCING THE HARMFUL-SUBSTANCE CONTENT OF FLUE GASES IN
A FURNACE UNIT 11 The invention relates to a method for reducing the harmful- substance content of f lue gases, as are usually released in a furnace unit in the course of a pyroprocess.
According to the type and quantity of the treated material and the fuel or gas used and the burning conditions, harmful substances contained in the material to be burnt, the fuel etc., like S02,1 HCl, NOx, HF or organic acids, are released and removed with the flue gases.
Numerous suggestions for reducing the harmful substances in the flue gases have been made in past decades. A substantial part of them relates to desulphurizing methods which operate predominantly in a damp medium. Thus, wet methods based on calcium are known, where with the use of burnt lime or limestone as adsorbing medium the gaseous harmful substances are washed out of the flue gas and are chemically bound. Calcium sulphate is produced as end product, it being partially dumped, partially used by the construction industry.
Such desulphurizing methods are used above all in power stations and large combustion installations. They require a very high expenditure in terms of apparatus and process technology and in part react extremely sensitively to fluctuations in the composition of the flue gas.
While the flue-gas cleaning for large installations of this kind is essentially technically solved, as before there is an urgent need to have a technique available for the flue-gas cleaning of small installations, which also operates reliably with greatly fluctuating emissions, requires low investment costs, enables a simple process technique and can be easily integrated into existing installations. In this connection, the invention has recognized that wet methods remove, and dry additive methods have, substantial advantages. In fact, the invention suggests in its most general embodiment a method for reducing the harmful- substance content of flue gases in a furnace unit having the following features: there is supplied to the furnace an oxide, inorganic adsorbing medium in combination with sodium carbonate (Na2CO3) or sodium hydrogen carbonate as additive, the dust-like particles of the adsorbing medium and of the additive concentrated with harmful substances (the furnace dust) are removed with the flue gas from the furnace and supplied to an at least two-stage filter for the separation of the furnace dust into different grain fractions, 20 the coarser fraction of the furnace dust separated in the first filter stage is supplied again at least partially in the circulation to the furnace, while the fine fraction of the furnace dust separated in 25 the second filter stage and concentrated with harmful substances is removed from the filter and disposed of. The flue-gas cleaning method operates with a dry adsorbing medium in combination with sodium (hydrogen) carbonate as additive. The harmful substances, in particular gaseous sulphur dioxide and hydrogen chloride, but also HF, NO, or organic acids, are extracted from the flue gas through accumulation on solid sorbents. The dry, contaminated reaction product formed in this way is separated by means of a filter. In this respect, in addition to the use of the combined sorbent, the arrangement of a two-stage filter R is essential, in which the furnace dust is divided into dif ferent grain fractions (a coarser one and a f iner one). It has namely been found that in particular with a fluctuating flue-gas characteristic property a secure binding of the harmful substances into the sorbents essentially depends on the following measures:
The harmful substances can accumulate in particular on the f iner particles of the furnace dust in a larger concentration (among other things due to a specifically higher surface).
The adsorbing action is also substantially dependent on the period of dwell of the adsorbing medium/additive in the furnace.
In this sense the separating of the f ilter for dividing of f a coarser fraction from a finer fraction and the at least partial return of the coarser fraction into the furnace favours the efficiency attainable with the method described twice over.
A particular advantage also consists in that the furnace dust which is already contaminated and returned from the f irst f ilter stage into the furnace can be supplemented by dusts of similar composition (for example from parallel furnace installations). In this respect, the adsorbing medium can itself consist at least in part of a material which is already contaminated.
An embodiment of the method provides to replace the oxide adsorbing medium up to 50% by mass with appropriate carbonate material.
With the f lue-gas cleaning of a rotating cylindrical furnace for the manufacture of sintered magnesite, the adsorbing medium could consist, for example, of dust-like caustic MgO, which is replaced by raw magnesite up to 50% by mass. The different grain sizes (caustic Mgo- < 500 pm, raw magnesite < 6 mm) in this respect at the same time promote an in-situ pelletizing or formation of granulated material in the rotating cylindrical furnace so that the caustic MgO can be removed from the furnace as clinker to a considerable extent. For such an application, which can analogously also be transferred to lime or dolomite furnacesl the particular advantage of a combination of a sintering process and a flue- gas cleaning is thus given.
The additive used (sodium carbonate or sodium bicarbonate) is in this respect added in accordance with an embodiment in a quantity of 0.5 to 2. 0 % by mass in relation to the solids delivered to the furnace. As a rule a mass portion of 1.0 % will suffice. The additive can be used in a grain fraction < 100 pm.
Dependent on the local conditions, the adsorbing medium can also be delivered to the furnace in the form of finer dusts (< 200 pm).
It has been found to be advantageous to select the furnace temperature to be so high that compared with normal operation an increased melting phase portion forms in the sinter material. This applies in particular to the named applications with the manufacture of sintered magnesite, sintered dolomite or suchlike, because in this way the pelletizing/formation of granulated material is promoted.
The separation grain size in the multistage filter is likewise selected in dependence upon the local prevailing conditions. In any case it is lower than the upper grain limit of the delivered adsorbing medium and amounts, for example, to 150 pm or less.
The portion of the adsorbing medium returned from the first filter stage into the furnace is set such that the solid particles in each case have such an adequately long period of dwell in the furnace that the desired degree of decontamination of the flue gas is achieved. In this respect, through repeated circulatory guiding of the coarser dust fraction and thus an increased period of dwell of the adsorbing material in the furnace, an increasing optimization of the flue-gas cleaning is achieved.
4 5; I. 1 At the same time it is to be ensured that the quantity of supplied additive is adjusted such that the sinter material removed from the furnace has as low a content of alkalis as possible, which in the event of the manufacture of sintered magnesite should not exceed 0.2 by mass.
Even if the chemical reaction processes with the use of the method described have not yet been definitively clarified, tests have shown that with the use of caustic magnesite as adsorbing medium and sodium hydrogen carbonate as additive the following chemical reactions occur:
with the adsorbing medium caustic MgO:
S02 + MgO M9S03 M9S03 + k02 M9S04 2 HCl + MgO M9C12 + H20 with the additive sodium bicarbonate:
S02 + '02 + 2NaHCO3 = Na2S04 + H20 + 2C02 HCl + NaHC03 = NaCl + H20 + C02 The excellent combinatory ef fect is based among other things also on the high basicity of the additive promoting the absorption, and the specific surface properties of the adsorbing medium used.
The method described can be realized without great constructional expenditure. It is suitable in particular for small installations, like sinter furnaces, refuse combustion installations etc.. The operational costs are low. In particular when the adsorbing medium at the same time serves the manufacture of a burnt end product, the costs for this are negligible. However, above all the method can also be used with greatly fluctuating emissions in the flue gas, whereby it presents itself to measure the harmful -substance concentrations in the f lue gas continuously and - in dependence on the values determined in this way - to regulate the addition quantity of the adsorbing medium/additive and/or the quantity of the returned dust from the f irst f ilter stage.
The method can be used both with discontinuous and with continuous operating conditions.
Tests have shown that emission values with S02 of 1, 320 to 1, 830 mg/Nm3 f lue gas with peaks to over 6, 000 mg/Nm' can be reduced with the method in accordance with the invention to values under 250 mg/NM3. With HC1, values of about 200 mg/Nm3 (with peaks to 1,700 mg/NM3) could be reduced long-term to values below 30 mg/NM3. These indications refer to a furnace for burning sintered magnesite with the use of caustic MgO as adsorbing medium, which was replaced to 20 -W by mass with raw magnesite (< 6 mm) and the addition of 1.0 % by mass (in relation to the remaining solids) of f inely-grained sodium bicarbonate.
W 101

Claims (15)

CLAIMS 1. Method for reducing the harmful-substance content of f lue gases in a furnace unit having the following features: 1.1 an oxide, inorganic adsorbing medium in combination with sodium carbonate or sodium hydrogen carbonate as additive is supplied to the furnace, 1.2 the dust-like particles of the adsorbing medium and the additive concentrated with harmful substances (the furnace dust), are removed with the f lue gas from the furnace and supplied to an at least two-stage f ilter for the separation of the furnace dust into different grain fractions, 1.4 the coarser fraction of the furnace dust separated in the f irst f ilter stage is again supplied at least in part in the circulation to the furnace, while the fine fraction of the furnace dust separated in the second filter stage and concentrated with harmful substances is removed from the f ilter and disposed of.
1.3 1.5
2. Method according to claim 1 with the condition that MgO and/or CaO is (are) used as oxide adsorbing medium.
3. Method according to claim 1 or 2 with the condition that the adsorbing medium is used in a grain fraction < 500 pm.
4. Method according to claim 3 with the condition that the adsorbing medium is used in a grain fraction < 200 pm.
5. Method according to one of claims 1 to 4 with the condition that the portion of the sodium (hydrogen) carbonate, in relation to the total mass of the solids delivered to the furnace, amounts to 0.5 to 2.0 by mass.
6. Method according to one of claims 1 to 5 with the condition that the sodium (hydrogen) carbonate is used in a grain fraction < 100 pm.
-C
7. Method according to one of claims 1 to 6 with the condition that the oxide adsorbing medium is replaced up to 50% by mass with an appropriate carbonate material.
8. Method according to claim 7 with the condition that the carbonate material is used in a grain fraction < 6 mm.
9. Method according to one of claims 1 to 8 with the condition that the furnace temperature is selected to be so high that compared with normal operation an increased melting phase portion forms in the treated material.
10. Method according to one of claims 1 to 9 with the condition that the separation grain size between the first and second filter stage is set to a value which is smaller than the upper grain limit of the newly delivered adsorbing medium.
11. Method according to claim 10 with the condition that the separation grain size between the first and second filter stage is set at 150 pm or smaller.
12. Method according to one of claims 1 to 11 with the condition that in each case so much furnace dust is returned from the first filter stage into the furnace 1 -g- that the solid particles in each case have such a sufficiently long period of dwell in the furnace until the desired degree of decontamination of the f lue gas is achieved.
13. Method according to one of claims 1 to 12 with the condition that in each case so much furnace dust is returned from the first filter stage into the furnace and the quantity of the returned sodium (hydrogen) carbonate is set such that the sintered material removed from the furnace has a maximum content of alkalis of 0. 2 % by mass.
14. Method according to one of claims 1 to 13 with the condition that the finely-grained, contaminated, dust-like material removed from the second filter stage is dumped.
15. Method substantially as herein described as an exemplary embodiment.
GB9320054A 1992-10-02 1993-09-29 Method for reducing the harmful-substance content of flue gases in a furnace unit Expired - Fee Related GB2271560B (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE4233119A DE4233119C1 (en) 1992-10-02 1992-10-02 Process for reducing the pollutant content of flue gases in a furnace unit

Publications (3)

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GB9320054D0 GB9320054D0 (en) 1993-11-17
GB2271560A true GB2271560A (en) 1994-04-20
GB2271560B GB2271560B (en) 1995-07-05

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AT (1) AT399462B (en)
DE (1) DE4233119C1 (en)
FR (1) FR2696472B1 (en)
GB (1) GB2271560B (en)
IE (1) IE66759B1 (en)
IT (1) IT1272713B (en)
SK (1) SK104693A3 (en)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5688479A (en) * 1994-12-22 1997-11-18 Uop Process for removing HCl from hydrocarbon streams
US8715600B1 (en) * 2013-05-16 2014-05-06 Babcock & Wilcox Power Generation Group, Inc. Circulating dry scrubber

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3960279A1 (en) * 2020-09-01 2022-03-02 Primetals Technologies Austria GmbH Recycling of valuable materials from exhaust gas purification

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2135662A (en) * 1983-02-26 1984-09-05 Steinmueller Gmbh L & C Method of binding sulphur compounds which are formed as reaction products during the combustion of fuels containing sulphur in a furnace

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3329342C2 (en) * 1983-08-13 1986-10-30 L. & C. Steinmüller GmbH, 5270 Gummersbach Process for the treatment of flue gases from a steam generating plant
DE3521002A1 (en) * 1984-01-07 1986-12-18 Hölter, Heinz, Dipl.-Ing., 4390 Gladbeck Fluidised-bed technology for relatively small heat outputs with a fraction separator in the region of the firing space
DE3717191C1 (en) * 1987-05-22 1988-08-25 Energie Versorgungssyst Evs Process for immobilising halogens on solids during the combustion of fossil fuels, refuse or the like
AT388883B (en) * 1988-02-01 1989-09-11 Waagner Biro Ag METHOD FOR THE SIMULTANEOUS TREATMENT OF Noxious Gases From Exhaust Gases
AT388312B (en) * 1987-07-29 1989-06-12 Waagner Biro Ag Process and device for the dry, simultaneous separation of pollutants and reactor for carrying out the process
DE3808586A1 (en) * 1988-03-15 1989-09-28 Paul Heilemann Process and plant for decreasing the pollutant content in the exhaust gas of an exhaust gas source
GB8813270D0 (en) * 1988-06-04 1988-07-06 Plasma Products Ltd Dry exhaust gas conditioning
DE4031379A1 (en) * 1990-04-27 1991-10-31 Sueddeutsche Kalkstickstoff Reducing pollutant emissions in combustion processes - by spraying soln. contg. cyanamide, di:cyanamide and water-soluble calcium cpd. into combustion chamber

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2135662A (en) * 1983-02-26 1984-09-05 Steinmueller Gmbh L & C Method of binding sulphur compounds which are formed as reaction products during the combustion of fuels containing sulphur in a furnace

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5688479A (en) * 1994-12-22 1997-11-18 Uop Process for removing HCl from hydrocarbon streams
US8715600B1 (en) * 2013-05-16 2014-05-06 Babcock & Wilcox Power Generation Group, Inc. Circulating dry scrubber
US9097158B2 (en) 2013-05-16 2015-08-04 Babcock & Wilcox Power Generation Group, Inc. Solids transport in flue gas desulfurization system

Also Published As

Publication number Publication date
ATA192893A (en) 1994-10-15
AT399462B (en) 1995-05-26
IE66759B1 (en) 1996-02-07
SK104693A3 (en) 1994-05-11
IT1272713B (en) 1997-06-26
GB9320054D0 (en) 1993-11-17
FR2696472A1 (en) 1994-04-08
ITMI932087A0 (en) 1993-09-30
DE4233119C1 (en) 1993-12-09
IE930736A1 (en) 1994-04-06
FR2696472B1 (en) 1995-06-09
GB2271560B (en) 1995-07-05
ITMI932087A1 (en) 1995-03-30

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 19970929